Color photography



UNITED STATES PATENT OFFICE COLOR PHOTOGRAPHY Edmund B. Middleton and Andrew B. Jennings,

New Brunswick, N. 1., assignors, by memo usignments, to Du Pont Film Manufacturing Corporation, a corporation of Delaware No Drawing. Application February 19, 1937,

Serial No. 128,735

12 Claims. (01. 95-88) This invention relates to color photography, oi the diamino-aryl class, such as p-phenyleneand more particularly to color-forming comdiamine or its substitution products, such as for pounds which form dyes by coupling with the example, di-methyl or di-ethyl p-phenylenedioxidation products of photographic developing amine. Color-forming compounds already proagents. posed include, for example, thymol, benzoyl ace- A principal object of this invention is to protone, phenac'yl chloride and para-nitrobenzyl vide a color photographic element derived from cyanide. color-forming compounds, which, in combina- These prior processes, however, have failed tion with certain classes of developing agents, to produce colored images having the correct will form dyes-in situ with photographic images. spectral qualities for color photography. More- A further object is to produce such dyes by colorover, these prior color-formers tend to have a forming development. Another object is to proharmful effect on the sensitivity of silver halide duce partial color-records in which the individual emulsions, so that, for these reasons, the colorrecords are of improved spectral quality for color formers already known have not provided a photography. practical means for color photography.

It has been formerly taught to prepare colored The present invention has demonstrated that photographs by developing exposed silver salt amino-aryl-bis-azoles wherein two amino hyemulsion layers in certain developing agents drogens of a diaminoaryl-bis-azole are replaced whose oxidation products are water-insoluble by the radicle of an acyl acetic acid, in conjuncdyes. Thus,a silver halide layer, bearing alatent tion with aromatic amino developing agents, image, can be developed in an alkaline indoxyl form satisfactory dye images when developing exsolution, whereupon a silver image is produced posed photo-sentitive layers of gelatino-silver along with a blue dye image in situ with the salts or bichromatized gelatin. Asrepresentative silver. The silver image can be removed by of the type of color-forming compounds contem- Fa'rmers Reducer, revealing the dye image. In plated as within the scope of our invention, are like manner, a photographic record can be dediacylacetaminoaryl bis azoles wherein two veloped in chlor-indoxyl to produce a green image amino hydrogens are replaced by the radicles of and in thio-indoxyl for a red image. v an a'cyl acetic acid e. g., acetoacetic acid, furoyl- It is also known, for the purpose of preparing acetic acid, benzoylacetlc acid and naphthoylcolor pictures, to develop exposed silver halide acetic acid and/or cyanacetic acid, malonic acid layers by agents whose oxidation products are and the azoles include the thiazoles; oxazoles, not colored but which will chemically unite or selenazoles and tellurazoles. The acylacetaminocouple with other organic agents, called coloraryl-bis-azoles may be made by condensing the formers" to form intensely colored dyes. These diaminoaryl-bis-azole with at least two mols of color-formers" are not photographic developers, the ethyl or equivalent ester of the acylacetic acid. are generally water-insoluble and produce dyes The following preferred examples are given as in situ with, and simultaneously with the depodescriptive of the invention but not in limitation sition of .the metallic silver image. The dethereof:

' Diacetoacetamino-l,2.afi-bcnzo-bis-thlazole 40 /s N\ CHa-(l0-CHrC0NEC\ /C--NHOCCH:OCCH: s

Diacetoacetamlno-l, Z 4. o-bonm-bis-selonazolo /s.

CHz-CO-CHrCO-NH-GX cNH-oc-cH -oc-cm Diiuroylacetamigo-l, 2- 4, ii-bfi nzo-biathiuole ClHlO-CO-CH1C0-NEC CNH0GGHrOC0OaHa B/ 56 velopers used for these proposed processes are The preferred color-forming compounds above described may be used either in developers or as an addition to silver halide emulsions.

As preferred color-forming developers, the following produce excellent results:

7 Formula 1 Diethyl-p-phenylenediamine, hydrochloride gms 2 Sodium sulfite, anhydrous gms Sodium carbonate, anhydrous gms 20 Water to liter 1 To which is added:

Diacetoacetamino-1,2,4,5-benzo-bis-thiazole gm 1.0 Ethyl alcohol cc 100 Formula 2 Diethyl-p-phenylenediamine, hydrochloride gms-.. 2 Sodium sulfite, anhydrous gms 5 Sodium carbonate, anhydrous gms 20 Water to "liter... 1 To which is added:

Diacetoacet'amino-1,2,4,5-benzo-bis-selenazole gm 1.0 Ethyl alcohol cc 100 Formula 3 Dimethyl-p-phenylenediamine, hydrochloride gms 2 Sodium sulfite, anhydrous gms 5 Sodium carbonate, anhydrous gms 20 Water to liter 1 To which is added: Difuroylacetamino- 1,2,4,5 benzo bis thiazole gm 1.0 Ethyl alcohol cc 100 In place of the di-alkyl-substituted p-phenylenediamine, the mono-alkylatedsubstitution products may be used or the un-substituted pphenylenediamine may be used as well as the pounds may be coated as layers on one or both sides of a photographic support either as individual or superposed emulsion layers.

While it is preferred to employ silver-gelatine emulsions, other emulsions comprising other well known sensitizers and binding agents'may also be used. Examples of these are the well known silver collodion emulsions, albuminoid emulsions, or bichromated emulsions.-

In the form of color-forming developers, the

above described compounds may also be used to re-develop bleached silver images. Thus, a silver image may be bleached in potassium ferrocyanide or a mixture of chromic and hydrobromic acids and re-exposed, whereupon the bleached image can be re-developed to silver and a dye image by the color-forming developers above described. After development, the silver is removed by any of the well known reducers such as Farmers Reducer.

While the foregoing'specification sets forth the preferred exemplifications of the present invention, it is intended to include all variations and modifications within the spirit and scope of the appended claims.

We claim:

1. A color-forming photographic developer comprising an aromatic amino photographic developing agent and a diacylacetaminoaryl-bisazole.

2. A color-forming photographic emulsion comprising a binding agent, a light sensitive compound, an aromatic amino photographic developing agent, and a compound taken from the group consisting of diacylacetaminoaryl-bis -oxazoles, thiazoles, and -selenazoles.

3. A color-forming photographic emulsion comprising a binding agent, a light sensitive compound, a compound selected from the group consisting of N-dialkyl-p-phenylenediamine and the acid salts thereof, and a compound taken from the group consisting of diacylacetaminoaryl-bis- -oxazoles, -thiazoles, and -selenazoles.

4. A color-forming photographic emulsion comprising a binding agent, a salt of silver and a diacylacetaminoaryl-bis-azole.

5. A color-forming photographic layer comprising a sensitized gelatlno-silver-halide emulsion and a diacylacetaminoaryl-bis-azo1e.

6. A color-forming photographic developer comprising an N-di-alkyl-p-phenylenediamine and a diacylacetaminoaryl-bis-azole.

7. A color-forming photographic emulsion comprising a binding agent, a silver halide and a diaoylacetamino-aryl-bis-thiazole.

8. A color-forming photographic emulsion comprising a binding agent, a silver halide and a diacetoacetaminobenzo-bis-thiazole.

9. A color-forming photographic emulsion comprising a binding agent, a silver halide and a diacylacetaminoaryl-bis-selenazole.

10. A color-forming photographic emulsion comprising a binding agent, a silver halide and a diacetoacetaminobenzo-bis-selenazole.

11. A color-forming photographic emulsion comprising a binding agent, a silver halide and a dinaphthoylacetaminoaryl-bis-azole.

12. A color-forming photographic emulsion comprising a silver halide and a dinaphthoylacetaminobenzo-bis-thiazole.

EDMUND B. MIDDLETON. ANDREW B. JENNINGS. 

